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I have a postfix mail server for our firm. The mails sent from this server to gmail and yahoo goes in spam.

The postfix is configured on our server and it has never been used for spamming.

Everything is configured as is should. The server works fine, the headers are as they should be.

What should I do in order the messages not to go in spam ?


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migrated from Apr 30 '10 at 9:36

This question came from our site for professional and enthusiast programmers.

up vote 2 down vote accepted

Take this Email Server Test and it will tell you what you can do deliver your emails cleanly.

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Check the headers of the email received by GMail and Yahoo accounts for hints as to why they are being marked as spam.

As Berkay said, it could be SPF-related; the headers should show this, e.g.

Authentication-Results:; spf=pass 
( domain of designates as permitted sender)

It doesn't sound like you're blacklisted, else other domains would have issues with your email, but DNSBL can be used to check your IP if you need to.

The article that itsadok linked to gives a good overview of things to check.

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+1 as you mentioned how to check for SPF related headers. This has been the most frequent cause mail sent via my mailserver ending up in the spam folder. – dunxd Apr 30 '10 at 10:35

Jeff recently published a blog entry on Coding Horror called So You'd Like To Send Some Email (Through Code). This has quite a number of good tips for what you can do to make your sending email more acceptable to external services.

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it can be due to the failing of SPF checks. read here to get information about SPF( Sender Policy Framework)

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This article has a great list of thing you should check. Its main points:

  1. Don't send spam
  2. Remove Your Server From Spamhaus’s Blocklists
  3. Configure Reverse DNS Lookups
  4. Format Messages Properly
  5. Create SPF Records
  6. Send All Messages From the Same Address
  7. Sign Email With DomainKeys or DKIM
  8. Use ‘Precedence: bulk’ for Bulk Emails?
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You may want to read this blog entry : "Postfix with DKIM, Domainkeys, SPf and Sender-ID" at

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Just to be safe, check your mx entries and check if you are blacklisted.

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